Instrument seal

ABSTRACT

A surgical access port comprises a valve or instrument seal that separates the instrument contact function from the instrument conforming function. Embodiments of the instrument seal comprise in instrument contact element that extends through an opening in a compression element, thereby defining an instrument orifice that seals with an instrument extending therethrough. Embodiments of the instrument contact element comprise a non-distensible membrane or film, for example, as a tube or cylinder.

CROSS-REFERENCE TO RELATED APPLICATION

This is application is a continuation of U.S. patent application Ser.No. 12/405,040, filed Mar. 16, 2009, which claims the benefit of U.S.Application No. 61/036,838, filed Mar. 14, 2008, the entire disclosuresof which are incorporated by reference.

BACKGROUND

1. Technical Field

This application generally relates to a medical device, and moreparticularly, to a surgical access device comprising a seal comprisingan instrument contact element extending through a compression element.

2. Description of the Related Art

Minimally invasive surgery is a type of surgery in which instrumentsaccess the interior of a patient's body through one or more surgicalaccess devices traversing a body wall. Laparoscopic surgery is a type ofminimally invasive surgery. Surgical access devices used in minimallyinvasive surgery include trocars or cannulas, single ports, and handports. Instruments access the interior of the patient's body through aninstrument access channel in the access device, which includes a valveor seal that forms a seal with the instrument.

In some cases, a surgical procedure is performed in a body cavityinflated or insufflated with an insufflation gas, for example, carbondioxide, which lifts an overlying body wall away from an organ bedwithin the body cavity, thereby providing a surgeon with a lessobstructed surgical field. Where the body cavity is the abdomen, theinsufflated condition is referred to as “pneumoperitoneum”. Surgicalaccess devices used under pneumoperitoneum seal the access channel bothin the presence and the absence of instruments extending therethrough,thereby preventing loss of pneumoperitoneum.

A typical trocar seal includes an elastic septum seal and a shield thatprotects the septum seal from damage, for example, tears and/orpunctures, from contact with instruments. Typical septum shields and/orprotectors, however, do not protect the orifice of the septum fromdamage. An exposed portion of the septum seal around the orificedirectly contacts and seals against the instrument. Exposing the edge ofthe septum around the orifice to an instrument exposes a vulnerableportion of the seal to aggressive surface features found on someinstruments. The exposed portion of the septum seal around the orificeis placed under immense stress while an instrument is inserted throughthe trocar, making the material around the orifice susceptible to nicksor cuts caused by contact with surgical instruments, particularlyinstruments that include sharp edges, undercuts, protuberances, and/orother challenging geometries.

Numerous technical challenges confront those designing and manufacturingseptum seals, for example, handling irregularly shaped surgicalinstruments, and balancing durability with drag force or frictionbetween the seal and surgical instruments. Elastomeric seal materialselongate when instruments are inserted, thereby increasing drag force.For example, a thick septum is resilient and durable, but exhibits ahigh instrument drag force from overcoming the restoring force generatedby expanding a small diameter orifice with a large diameter instrument.Oil canning, or inversion, of typical septum seals can also result inloss of precise instrument movement because the surgeon experiences adifferent feedback or feel between large and small changes in theposition of the instrument. An hour-glass-shaped septum seal can bestretched during instrument insertion, which also increases the dragforce.

SUMMARY OF THE INVENTION

A surgical access port comprises a valve or instrument seal thatseparates the instrument contact function from the instrument conformingfunction. Embodiments of the instrument seal comprise in instrumentcontact element that extends through an opening in a compressionelement, thereby defining an instrument orifice that seals with aninstrument extending therethrough. Embodiments of the instrument contactelement comprise a non-distensible membrane or film, for example, as atube or cylinder. Some embodiments of the instrument contact elementhave an hourglass configuration with a first end proximal of the openingof the compression element and a second end distal of the opening of thecompression element. Other embodiments of the instrument contact element“wrap around” the opening in the compression element, with the first endand the second end secured to the same side of the opening, for example,proximal of the opening. Embodiments of the compression element comprisean elastomeric seal, for example, a septum seal and/or a gel seal.

Some embodiments provide a surgical access device comprising aninstrument seal, the instrument seal comprising: a longitudinal axisalong extending from a proximal end to a distal end; an instrumentaccess channel extending along the longitudinal axis; a seal housing; anelastic compression element disposed in the seal housing, comprising anopening aligned with the access channel; and a non-distensibleinstrument contact element disposed on the compression element andextending through the opening in the compression element, therebydefining an instrument orifice. The instrument seal has a first state inthe absence of an instrument extending through the orifice, and theinstrument seal has a second state in the presence of an instrumentextending through the orifice in which the instrument contact elementseals against the instrument.

In some embodiments, the elastic compression element comprises a septumseal. In some embodiments, the elastic compression element comprisespolyisoprene. In some embodiments, an elongation of the elasticcompression element is at least about 600%.

In some embodiments, the instrument contact element comprises apolyolefin film. In some embodiments, the instrument contact element issubstantially cylindrical in an unconstrained state. In someembodiments, a smallest constrained diameter of the instrument contactelement is at least at large as a diameter of a largest instrument thatthe instrument seal is designed to accommodate.

In some embodiments, the surgical access device is a trocar comprising aseal assembly comprising the instrument seal; and a cannula extendingfrom the seal assembly, wherein the access channel extends through theseal assembly and the cannula. Some embodiments further comprise a zeroseal aligned with the access channel.

Some embodiments provide a surgical access device comprising aninstrument seal, the instrument seal comprising: a longitudinal axisalong extending from a proximal end to a distal end; an instrumentaccess channel extending along the longitudinal axis; a seal housing; anelastomeric compression element disposed in the seal housing; and anon-distensible instrument contact element extending from the proximalend to the distal end of the instrument seal, and through thecompression element defining an orifice through which the access channelextends. The instrument seal has a first state in the absence of aninstrument extending through the orifice, and the instrument seal has asecond state in the presence of an instrument extending through theorifice in which the instrument contact element seals against theinstrument.

In some embodiments, surgical access device is a trocar comprising aseal assembly comprising the instrument seal; and a cannula extendingfrom the seal assembly, wherein the access channel extends through theseal assembly and the cannula. In some embodiments, the surgical accessdevice is a hand port.

In some embodiments, the compression element comprises a gel material.In some embodiments, the gel material has an elongation of at leastabout 1,000%. In some embodiments, the compression element comprises aplurality elastic elements defining an opening through with theinstrument contact element extends, wherein least some elastic elementsoverlap at least one other elastic element. In some embodiments, thecompression element comprises a septum seal. In some embodiments, thecompression element is disc-shaped. In some embodiments, the compressionelement is toroidal. In some embodiments, the compression element istethered to the seal housing.

In some embodiments, the instrument contact element comprises apolyolefin film. In some embodiments, the instrument contact element issubstantially cylindrical in an unconstrained state. In someembodiments, the instrument contact element comprises at least one slit.Some embodiments further comprise a lubricant disposed on at least aportion of the instrument contact element. In some embodiments, a distalend of the instrument contact element is secured to a disk weight.

In some embodiments, in the first state, the instrument seal is a zeroseal. In some embodiments, in the first state, the instrument contactelement at the orifice comprises a plurality of folds.

In some embodiments, the instrument seal has a leak rate of less thanabout 500 mL/min at 2 kPa in the second state.

Some embodiments further comprise a zero seal through which the accesschannel extends.

In some embodiments, in the second state, the instrument contact elementspaces the instrument from the compression element.

Some embodiments provide a surgical access device comprising aninstrument seal, the instrument seal comprising: a longitudinal axisalong extending from a proximal end to a distal end; an instrumentaccess channel extending along the longitudinal axis; a seal housing; atubular instrument contact element longitudinally disposed in the sealhousing, through which the access channel extends; and an elasticcompression element disposed around the instrument contact element,compressing a portion thereof, thereby defining an orifice. A smallestuncompressed diameter of the instrument contact element is at least atlarge as a diameter of a largest instrument that the instrument seal isdesigned to accommodate, the instrument seal has a first state in theabsence of an instrument extending through the orifice, and theinstrument seal has a second state in the presence of an instrumentextending through the orifice in which the instrument contact elementseals against the instrument.

In some embodiments, the instrument contact element comprises anon-distensible material. In some embodiments, the non-distensiblematerial comprises a polyolefin film. In some embodiments, theinstrument contact element comprises an elastomeric material.

Some embodiments provide a surgical access device comprising aninstrument seal, the instrument seal comprising: a longitudinal axisalong extending from a proximal end to a distal end; an instrumentaccess channel extending along the longitudinal axis; a seal housing; atubular instrument contact element longitudinally disposed in the sealhousing, and through which the access channel extends, the instrumentcontact element comprising a first end operatively coupled to the sealhousing and a second end floating within the seal housing; and anelastic compression element disposed around the instrument contactelement, compressing a portion thereof, thereby defining an orifice, andsecured within the seal housing by the instrument contact element. Theinstrument seal has a first state in the absence of an instrumentextending through the orifice, and the instrument seal has a secondstate in the presence of an instrument extending through the orifice inwhich the instrument contact element seals against the instrument.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view of a surgical access device comprising anembodiment of an instrument seal. FIG. 1B is an exploded perspectiveview and FIG. 1C is a cross-sectional view of a seal assembly of theaccess device illustrated in FIG. 1A. FIG. 1D is a cross section of theinstrument seal illustrated in FIGS. 1B and 1C. FIG. 1E is a crosssection of an instrument contact element of the instrument seal of FIG.1D in an unconstrained state. FIG. 1F is a side view of a compressionelement of the instrument seal of FIG. 1D.

FIG. 2 is a cross section of an access device comprising anotherembodiment of an instrument seal.

FIG. 3A is a cross section of an access device comprising anotherembodiment of an instrument seal. FIG. 3B is an exploded view of a sealassembly of the access device of FIG. 3A. FIG. 3C is a cut-away view ofa compression element of the seal assembly illustrated in FIG. 3B.

FIG. 3D is a cross-sectional view of the access device of FIG. 3A-3Cwith an instrument inserted therein. FIG. 3E is a cross-sectional viewof the access device of FIG. 3A-3C with a larger instrument insertedtherein. FIG. 3F is a cross-sectional view of the access device of FIG.3A-3C with a fork-tipped instrument inserted therein. FIG. 3G is across-sectional view of the access device of FIG. 3A-3C with aninstrument comprising an undercut inserted therein.

FIG. 4 is a cross section of an access device comprising anotherembodiment of an instrument seal.

FIG. 5 is a top view of an embodiment of an embodiment of a compressionelement comprising a star-shaped opening.

FIG. 6 is a perspective view of an embodiment of an embodiment of atoroidal compression element.

FIGS. 7A, 7B, and 7C are top, side, and cross-sectional views of anembodiment of a frustoconical compression element.

FIGS. 8A and 8B are perspective and top views of an embodiment of acompression element comprising a torus and a plurality of tethers.

FIG. 9 is a top view of an embodiment of a compression elementcomprising a rim and a plurality of elastic elements.

Similar elements have similar reference numbers.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

A valve or seal for a surgical access device comprises an instrumentcontact element and a compression element. Separating the instrumentcontact and the instrument conforming functions of the seal intoseparate components permits improving each function independently of theother, for example, through material selection, dimensioning, changes ingeometry, and the like. For example, one material may exhibit highpuncture resistance and low friction, while a second material exhibitshigh elongation and low modulus. Embodiments of the seal are useful insurgical access devices such as trocars, hand ports, single ports, andthe like.

FIG. 1A is a side view of a surgical access device 100, embodied as atrocar, comprising a proximal end, a distal end, and a longitudinalaxis. A tubular cannula 110 comprising a longitudinal lumen is disposedat the distal end and is coupled to a seal assembly 120 at the proximalend. An instrument access channel 102 extends through the cannula 110and seal assembly along the longitudinal axis in the illustratedembodiment. In the illustrated embodiment, the cannula 110 and sealassembly 120 are releasably coupled. In other embodiments, the cannula110 and seal assembly 120 are integrated. An O-ring 112 captured at theproximal end of the cannula 110 provides a fluid-tight seal between thecannula 110 and the seal assembly 120 in the illustrated embodiment.Embodiments of the cannula 110 are rigid or flexible.

FIG. 1B is an exploded perspective view and FIG. 1C is a cross-sectionalview of the seal assembly 120. The seal assembly 120 comprises a sealhousing 130 comprising a fluid connector 132. In the illustratedembodiment, the fluid connector 132 comprises a radially extending Luerfitting and a stopcock. A cap or cover 140 closes a proximal end of theseal housing 130, securing within the housing 130 an instrument seal 150and a zero seal 190.

In the illustrated embodiment, the cap 140 comprises a funneled entry142 at a proximal end thereof, and an alignment channel 144 distal ofthe funneled entry 142. The funneled entry 142 guides instruments intothe access channel 102, while the alignment channel 144 generally alignsan inserted instrument longitudinally with the access channel 102.Aligning the instrument with the access channel reduces instrumentcontact with off-axis portions of the device 100 or components thereof,thereby reducing damage thereto. The cap 140 is secured to the proximalend of the housing 130 using any suitable method, for example,mechanically (e.g., screw threads, clips, bayonet mounts, screws,latches, ratchets, pins, lock rings, flanges and grooves, splines),adhesively (e.g., glue, epoxy, urethane, cyanoacrylate, pressuresensitive adhesive, polyvinyl alcohol adhesive, butadiene-styreneadhesive), welding (e.g., thermal, solvent, electron beam, laser,ultrasonic), magnetically, and the like. In some embodiments, the cap140 is secured to the housing 130 by a combination of methods.

The cannula 110, housing 130, and cap 140 independently comprisesuitable biologically compatible materials or combinations thereof, forexample, metal, stainless steel, aluminum, nickel-titanium alloy,polymer resin, polycarbonate, polyester, polyamide (Nylon®, Delrin®),aramid (Kevlar®), polyimide, polyether block amide (PEBAX®), polyolefin,polyethylene (Spectra®), polypropylene, fluorinated polymers, epoxy,polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate,polyvinyl chloride (PVC), polysulfone, polyetheretherketone (PEEK),polyepoxide, polyacrylate, polyether, acrylonitrile-butadiene-styrene(ABS), rubber, synthetic rubber, polyisoprene, silicone, ethylenepropylene diene monomer (EPDM), ethylene-propylene copolymer (EPrubber), polybutadiene, polyurethane, styrene-butadiene, ethylene vinylacetate (EVA), polychloroprene (Neoprene®), perfluorelastomer (Kalrez®),thermoplastic elastomer (HYTREL®, PELLETHANE®, KRATON®), glass, ceramic,carbon fiber, and the like. Some embodiments of suitable materialscomprise copolymers, mixtures, blends, and/or alloys. Some embodimentsof suitable materials comprise a composite, for example, a fiberreinforced polymer. Those skilled in the art will understand thatdifferent portions of a component comprise different materials in someembodiments.

The zero seal 190 comprises a generally funnel-shaped duckbill valve ordouble duckbill valve in the illustrated embodiment. The duckbill valveseals in the absence of an instrument extending therethrough, therebypreventing gas flow through the access channel 102 in the absence of aninstrument and loss of pneumoperitoneum. In other embodiments, the zeroseal 190 comprises a different type of valve, for example, a flap valve.Some embodiments of the access device 190 do not comprise a zero seal.

Embodiments of the zero seal 190 comprise one or more suitablematerials. For example, some embodiments of the duckbill valve comprisean elastomeric material, for example, at least one of polymer resin,rubber, synthetic rubber, polyisoprene, silicone, ethylene propylenediene monomer (EPDM), ethylene-propylene copolymer (EP rubber),polybutadiene, polyurethane, styrene-butadiene, ethylene vinyl acetate(EVA), polychloroprene (Neoprene®), perfluorelastomer (Kalrez®),thermoplastic elastomer (HYTREL®, PELLETHANE®, KRATON®), as well asblends, mixtures, copolymers, and/or composites thereof. In someembodiments, the duckbill valve comprises polyisoprene.

As best seen in FIG. 1D, which is a cross section of the instrument seal150, the instrument seal 150 comprises a compression element 160 and aninstrument contact element 180. The instrument seal 150 is generallyfunnel-shaped with an orifice 152 disposed at a distal end thereof. Thefunnel shape of the instrument seal 150 creates a funnel entry forinstruments inserted through the access channel 102, with which theorifice 152 is aligned.

The compression element 160 comprises a proximal flange 162 extendingradially from the housing 130 towards the longitudinal axis of thetrocar 100. A distal region 164 of the compression element convergesfrustoconically, terminating in an opening 166. The illustratedembodiment of the flange 162 comprises a convolution or bellows thatfurnishes the distal end 164 with translational and rotational degreesof freedom, or “float”, which accommodates lateral, longitudinal, and/orangular movements of an instrument extending through the opening 166,while maintaining a seal with the instrument. The illustrated embodimentof the compression element 160 has a general form resembling a septumseal, and as such, is also referred to herein as a septum seal, althoughthe compression element 160 does not actually function as a septum seal.

FIG. 1E, which illustrates a cross section of the instrument contactelement 180 in an unconstrained or relaxed state, the instrument contactelement 180 comprises a tubular sheath, sleeve, or membrane 182comprising a first end and a second end. In the illustrated embodiment,the first end of the membrane 182 is coupled to a first ring 184. Asshown in FIG. 1D, the first ring 184 is disposed on an inner wall 168 ofthe compression element, for example, at or near the proximal end of thedistal region 164 of the compression element. In the illustratedembodiment, an outwardly extending flange 186 on the first ring engagesa groove 170 on the inner wall 168 of the compression element, therebycoupling the first ring 184 thereto. A second ring 186 is coupled to thesecond end of the membrane 182. The second ring 188 is disposed on anouter wall 170 of the compression element, and in the illustratedembodiment, engages proximal ends of a plurality of longitudinal ribs172 disposed on the outer wall 170 of the compression element, which arebest seen in FIG. 1F, a side view of the compression element 150. Insome embodiments, the ribs 172 also reinforce the compression element160, thereby reducing or preventing inversion thereof, for example, onwithdrawing an instrument. In some embodiments, the second ring 188 issecured in another way, for example, using a flange and/or a groove. Insome embodiments, the second ring 186 engages the first ring 184 throughthe compression element 160. In some embodiments, at least one of thefirst ring 184 and the second ring 186 is adhered and/or welded to thecompression element 160. Because the instrument contact element 180 isdisposed on the compression element 160 distal of the flange 162, theinstrument contact element 180 moves in concert with distal portion 164and opening 166 of the compression element. Consequently, the orifice152 of the instrument seal is always aligned with the opening 166 of thecompression element.

In the illustrated embodiment, the tubular membrane 182 extends throughthe first ring 184 and through the opening 166 in the compressionelement. The membrane 182 together with the opening 166, defines theorifice 152 in the instrument seal. The membrane 182 is doubled- orfolded-back through the opening 166, thereby wrapping the opening 166and distal region 164 of the compression element therewith, andprotecting the opening 166 and distal region 164 from damage. As bestseen in FIG. 1E, in an unconstrained state, the tubular membrane 182 isgenerally cylindrical. In the illustrated embodiment, a diameter of thetubular membrane 182 is at least as large as a diameter of a largestinstrument for which the access device 100 is designed to accommodate.The diameter of the tubular membrane 182 is larger than a diameter ofthe opening 166 in the compression element. Consequently, the distalportion 164 of the compression element compresses the portion of themembrane 182 that passes through the opening 166, thereby generating aplurality of folds, pleats, gathers, or wrinkles therein. The folds orpleats in the membrane 182 around the orifice 152 tend to direct a tipof an inserted instrument longitudinally towards the orifice 152.

Because the diameter of the tubular membrane 182 is at least as large asa diameter of the largest instruments, inserted instruments do notstretch the diameter of the tubular membrane 182. Because the membrane182 itself is not under tension even when the largest instrument isinserted therein, the membrane 182 does not compress the instrument,thereby reducing drag and friction therebetween. Instead of stretchingthe membrane 182, the instrument reduces and/or eliminates the fold orpleats when inserted. Durability is also improved by not stretching themembrane 182.

In the illustrated embodiment, the membrane compression element 182completely covers the opening 166. Consequently, an instrument insertedthrough the orifice contacts only the membrane 182 and does not directlycontact the opening 166 or the distal portion 164 of the compressionelement. In other words, the membrane 182 spaces or isolates theinstrument from the opening 166 or the distal portion 164 and thecompression element in the illustrated embodiment.

In the illustrated embodiment, the membrane 182 is substantially taut orunder tension between the first ring 184 and the second ring 188, actingas a trampoline, deflecting a tip of an instrument in contact therewithaway from the underlying compression element 160, thereby preventing orreducing damage thereto. In other embodiments, the membrane 182 is notunder tension. A looser membrane 182 generally accommodates moremovement and/or deformation of the compression element 160 than atighter membrane 182. In some embodiments, however, a looser membrane182 transmits rather than deflects force from an incident instrument tipto the underlying compression element 160. In some cases, thetransmitted force is sufficient to damage or puncture the compressionelement 160, sometimes without puncturing the membrane 182 itself.

In the illustrated embodiment, the membrane 182 is a closed tube. Inother embodiments, the membrane 182 comprises a tube with abutting oroverlapping longitudinal edges. The illustrated embodiment of themembrane 182 in an unconstrained state is generally cylindrical. Inother embodiments, the membrane 182 has another shape, for example,frustoconical, hourglass shaped, barrel shaped, or abutting cylinderswith different diameters. In other embodiments, the membrane 182 has adifferent cross-sectional shape, for example, elliptical, oval,polygonal, and the like.

Some embodiments of the membrane 182 comprise at least one slit, slot,or opening extending from proximal of the orifice 152 to distal of theorifice 152, for example, from the first end of the membrane 182 to thesecond end of the membrane 182. Some embodiments of the at least oneslit, slot, or opening are generally longitudinal, while otherembodiments are angled or at a bias with respect to a longitudinal axisof the membrane 182. In some embodiments, the at least one slit, slot,or opening generates one or more overlapping layers of the membrane 182at the orifice, thereby reducing or eliminating folds and/or pleats inthe membrane 182 at the orifice 152.

The distal region 164 of the compression element comprises anelastomeric material selected to compress the instrument contact element180 against an instrument extending through the orifice 152, therebyforming a seal therewith. In some embodiments, the entire compressionelement 160 comprises an elastomeric material. Some embodiments of theelastomeric material have an elongation of at least about 500%, at leastabout 600%, or at least about 700%. A material with a higher elongationgenerally seals with larger diameter instruments for a given compressionelement 160. Suitable elastomeric materials include polymer resin,rubber, synthetic rubber, polyisoprene, silicone, ethylene propylenediene monomer (EPDM), ethylene-propylene copolymer (EP rubber),polybutadiene, polyurethane, styrene-butadiene, ethylene vinyl acetate(EVA), polychloroprene (Neoprene®), perfluorelastomer (Kalrez®),thermoplastic elastomer (HYTREL®, PELLETHANE®, KRATON®), as well asblends, mixtures, copolymers, and/or composites thereof. In someembodiments, the compression element 160 comprises polyisoprene. Becausethe instrument does not directly contact the compression element 160 insome embodiments, coefficient of friction, strength, tear resistance,puncture resistance, and/or abrasion resistance of the material is notas important in these embodiments.

The membrane 182 comprises a material selected to provide at least oneof puncture resistance, tear resistance, tensile strength, durability,abrasion resistance, good sealing characteristics, flexibility, and lowfriction. Embodiments of the membrane 182 are substantiallynon-distensible under the working conditions of the access device 100.Examples of suitable non-distensible materials include polymer resin,polymer resin, polycarbonate, polyester, polyamide (Nylon®, Delrin®),aramid (Kevlar®), polyimide, polyether block amide (PEBAX®), polyolefin,polyethylene (Spectra®), polypropylene, fluorinated polymers, epoxy,polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate,polyvinyl chloride (PVC), polysulfone, polyetheretherketone (PEEK),polyepoxide, polyacrylate, polyether, acrylonitrile-butadiene-styrene(ABS), as well as blends, mixtures, copolymers, and/or compositesthereof. Some embodiments of the membrane 182 comprise a polyolefin.

Other embodiments of the membrane 182 are elastomeric or distensible,for example, comprising at least one of polymer resin, rubber, syntheticrubber, polyisoprene, silicone, ethylene propylene diene monomer (EPDM),ethylene-propylene copolymer (EP rubber), polybutadiene, polyurethane,styrene-butadiene, ethylene vinyl acetate (EVA), polychloroprene(Neoprene®), perfluorelastomer (Kalrez®), thermoplastic elastomer(HYTREL®, PELLETHANE®, KRATON®), as well as blends, mixtures,copolymers, and/or composites thereof. Embodiments of membranes 182comprising elastomeric or distensible materials provide improved sealingto the instrument and/or itself, while increasing friction or drag,which increases the likelihood of puncturing the membrane 182 and/ordecreases the durability thereof.

Some embodiments of the membrane 182 comprise a composite, for example,comprising a low friction surface layer or film, and a high strengthlayer or film. Some embodiments comprise reinforcing fibers, whichimprove strength. In some embodiments, the membrane 182 is anisotropic,for example, with high strength in a longitudinal direction and highfoldablity in a transverse direction.

Some embodiments of the membrane 182 comprise a coating comprising atleast one of an oil, silicone oil, thin gel film, and lubriciouscoating, which reduces friction with an instrument in contact therewith.In some embodiments, the coating also improves sealing with theinstrument, as well as self-sealing of the folds or pleats in themembrane 182. In particular, the membrane 182 comprises more and/orlarger folds or pleats in the presence of smaller instruments or noinstrument at all.

Some embodiments of the membrane 182 comprise a textured surface, whichreduces friction, for example, dots, bumps, stripes, ridges, and thelike. The texture is patterned or random.

Although a low friction for instrument movement in the instrument seal150 is desirable, some friction is desirable in some embodiments. Forexample, sufficient friction to maintain the position of an instrumentin the instrument seal 150 relieves a user from holding the instrumentin place to prevent undesired movement.

Embodiments of the membrane 182 are not greater than about 250 μm (about10 mil), not greater than about 125 μm (about 5 mil), not greater thanabout 25 μm (about 1 mil), not greater than about 12 μm (about 0.5 mil),not greater than about 5 μm (about 0.2 mil), or not greater than about 2μm (about 0.1 mil). Those skilled in the art will understand that thethickness of a membrane 182 will depend on the material and a balancingof desired properties of the membrane 182. For example, a thickermembrane generally has higher strength, tear resistance, punctureresistance, durability, and abrasion resistance. A thinner membranegenerally conforms better to an instrument and to itself, andaccordingly, seals better.

One criterion for quantifying the seal between the instrument seal 150and an instrument is a leak rate. While a zero leak rate may bedesirable in some cases, insufflators are capable of deliveringinsufflation gas at high rates, for example, up to about 30 L/min or upto about 40 L/min. Such an insufflator is capable of compensating forleaks from up to four or five access devices, each with an instrumentseal exhibiting a leak rate of up to about 400 mL/min, up to about 500mL/min, up to about 1,000 mL/min, or up to about 1,500 mL/min at about 2kPa (about 15 Torr, 8 inches of water). Leak rates are for instrumentseals 150 with and/or without an instrument inserted therein.

Embodiments of the access device 100 accommodate instruments ofdifferent sizes. For example, embodiments of the access device 100include trocars that accommodate instrument with diameters of up toabout 5 mm, up to about 8 mm, up to about 11 mm, up to about 12 mm, orup to about 15 mm. Some embodiments seal with instruments with diametersof from about 4.5 mm to about 15.4 mm. Some embodiments of the accessdevice 100 accommodate a surgeon's hand. Some embodiments of the accessdevice 100 comprise a plurality of instrument seals 150, therebypermitting the introduction of a plurality of instruments through asingle device.

FIG. 2 is a cross section of an embodiment of an access device 200similar to the embodiment illustrated in FIGS. 1A-1F. The access device200, embodied as a trocar, comprises a cannula 210 and a seal assembly220. The seal assembly 220 comprises a seal housing 230 and a cap 240,which capture an instrument seal 250 and a zero seal 290. The instrumentseal 250 comprises a compression element 260 and an instrument contactelement 280. In the illustrated embodiment, the instrument contactelement 280 comprises a membrane 282. A first end of the membrane 282 iscoupled to an inner wall 268 of the compression element. The membrane282 extends through an opening 266 that terminates a distal portion 264of the compression element. A second end of the membrane 282, disposeddistal of the opening 266, is coupled to a ring 288. An inner diameterof the ring 288 is about the same as a diameter of the membrane 282.

The ring 288 has a diameter greater than the diameter of the opening266, thereby preventing the second end of the membrane 282 from passingtherethrough. Some embodiments of the ring 288 comprise a disc weight,which tensions the membrane 282 when the access device 200 is in agenerally upright position as shown in FIG. 2. Some embodiments comprisea tensioning element (not illustrated) that urges the ring 288 distally,thereby maintaining the membrane 282 under tension when the accessdevice 200 is in other positions. The tensioning element itself is undertension, under compression, or comprises at least one component undertension and at least one component under compression. Embodiments of thetensioning element comprise, for example, at least one of a spring, anelastic band, a resilient member, a balloon, and the like. Someembodiments comprise a stop (not illustrated) that limits proximalmovement of the ring 288. Embodiments in which the ring 288 is free tomove within the seal housing 230 accommodate greater off-axis and/orangular positioning of an instrument.

In the illustrated embodiment, the membrane 282 has a generallyhourglass shape, with the opening 266 of the compression elementdefining a waist portion of the hourglass shape. The waist portion ofthe hour glass defines an orifice 252 of the instrument seal. The ring288 also keeps the second end of the membrane 282 open, therebymaintaining the hourglass shape of the membrane 282. The hourglass shapeof the membrane 282 provides a funnel entry to the orifice 252 for bothproximal and distal approaches thereto along an access channel 202 ofthe access device.

FIG. 3A is a cross section of another embodiment of an access device300, which is similar to the embodiments described above. The accessdevice 300 comprises a cannula 310 and a seal assembly 320. FIG. 3B isan exploded view of the seal assembly 320, which comprises a sealhousing 330, a cap 340, an instrument seal 350, and a zero seal 390. Theinstrument seal 350 comprises a compression element 360 and aninstrument contact element 380.

In the illustrated embodiment, the compression element 360 comprises agel disc comprising a generally circular opening 366 extendinglongitudinally through the center thereof as best seen in FIG. 3C. Theopening 366 is aligned with the access channel 302. In some embodiments,the opening 366 has a small diameter, for example, formed by passing aneedle through the compression element 360.

Embodiments of the compression element 360 comprise a gel material.Embodiments of suitable gel materials are biocompatible and exhibit highelongations, low durometer, and high tear strengths. Embodiments of thegel material comprise a thermoplastic elastomeric diblock and/or atriblock copolymer, and an oil. Examples of suitable diblock copolymersinclude styrene-ethylene/butylene (S-E/B), and the like. Examples ofsuitable triblock copolymers include styrene-ethylene/butylene-styrene(S-E/B-S), styrene-isoprene-styrene, (S-I-S), styrene-butadiene-styrene(S-B-S), styrene-ethylene/propylene-styrene (S-E/P-S), and the like.Examples of suitable diblock and triblock copolymers are commerciallyavailable as KRATON® (Kraton Polymers) and SEPTON® (Kuraray Co.). Insome embodiments, the copolymer is a KRATON® triblock copolymer.Examples of suitable oils include mineral oil, vegetable oil, petroleumoil, silicone oil, and mixtures thereof. In some embodiments, the oil ismineral oil. Embodiments of the gel material comprise at least about6:1, at least about 1:5, or at least about 1:10 KRATON® to mineral oilby weight. Embodiments of the gel material comprise up to about 1:15KRATON® to mineral oil by weight.

Some embodiments of the gel material exhibit an ultimate elongation ofat least about 1000 percent and a durometer less than about 5 Shore A,and are referred to ultragels. Some embodiments exhibit an ultimateelongation of at least about 1500 percent and a durometer less thanabout 200 Bloom. Some embodiments exhibit an ultimate elongation of atleast about 3000 percent. Embodiments of gel and ultragel materials havea tacky or sticky surface. In some embodiments, the surface is treatedto reduce the tackiness, for example, by powdering and/or skinning witha polymer film. In other embodiments, the surface is untreated becausethe instrument contact element 380 is disposed between the compressionelement 360 and an instrument extending through the opening 366, therebypreventing contact therebetween.

As discussed above, a higher elongation material seals with largerinstruments. Consequently, embodiments of gel compression elements 360with higher elongations are capable of sealing with instruments with awider range of diameters than similar compression elements comprisinglower elongation materials. Accordingly, in some embodiments, theorifice 352 has a zero or near-zero diameter in the absence of aninstrument, while still able to seal larger instruments. In some ofthese embodiments, the leak rate of the instrument seal 350 without aninstrument inserted therethrough is sufficiently low that an insufflatoris capable of compensating for the leak, as discussed above. In some ofthese embodiments, the instrument seal 350 functions as a zero seal, andconsequently, the zero seal 390 is optional.

Embodiments of gel materials also exhibit a low modulus. Otherwisesimilar compression elements, one comprising gel and the othercomprising rubber, will exhibit very different correlations betweeninstrument drag and instrument diameter. With the largest diameterinstrument that the rubber compression element will accommodate insertedtherein, the rubber is close to the elastic limit on the stress-straincurve where the modulus is high. In contrast, with the same diameterinstrument inserted in the gel compression element, the gel is not closeto the elastic limit. In this region of the stress-strain curve, themodulus is low. Consequently, differences in the force required toinsert instruments of different diameters are smaller for the gelcompression element compared with the rubber compression element,resulting in a more consistent instrument drag for the gel compressionelement.

The compression element 360 applies only compression in response to aninstrument inserted in the opening 366 rather than any twisting orrotational forces. Accordingly, the high elongation materials, includinggels and ultragels, also conform more effectively to out of round andnon-round shapes, thereby improving sealing to instruments with suchcross sections.

Some embodiments of the compression element 360 comprise a foamed softelastomer with properties similar to the gel and/or ultragel materialsdiscussed above, for example, foamed KRATON®, foamed MONOPRENE®(Poly-Med Inc.), and the like.

As discussed above, the instrument contact element 380 prevents contactbetween the compression element 360 and an instrument, therebypermitting the use of the soft and easily damaged materials discussedabove.

The instrument contact element 380 comprises membrane 382 extendingthrough the opening 366 in the compression element, with a first endproximal of the compression element 360 and a second end distal of thecompression element 360. In the illustrated embodiment, the first end ofthe membrane 382 is coupled to a first ring 384 which is capturedbetween the cap 340 and the seal housing 330, thereby securing the firstend of the membrane 382. In other embodiments, the first end of themembrane 382 is secured in another way, for example, operatively coupledto a distal end of the alignment channel 344 of the cap. The second endof the membrane 382 is coupled to a second ring 388. An inner diameterof the second ring 388 is about the same as the diameter of the membrane382 in the illustrated embodiment. Some embodiments of the second ring388 comprise a disc weight, as discussed above. Also as discussed above,some embodiments of the instrument contact element 380 comprise anoptional tensioning element and/or stop for the second ring 388. Inother embodiments, the second end of the membrane 382 is operativelycoupled to the seal housing 330, for example, through the second ring388, and the first end floats.

The membrane 382 in the illustrated embodiment has a generally hourglassshape with the portion of the membrane 382 extending through the opening366 in the compression element defining an orifice 352 in the instrumentseal 350, which is aligned with the access channel 302. The first ring384 and the second ring 388 of the instrument contact element capturethe compression element 360 therebetween, thereby securing thecompression element 360. Accordingly, the compression element 360 canfloat laterally in concert with lateral movements of instruments in theaccess channel 302, thereby tracking the instrument. As discussed above,the hourglass shape of the membrane 382 defines funnel entries for bothinserting and withdrawing instruments into and from the orifice 352 ofthe instrument seal, respectively.

Interactions between embodiments of the instrument seal and variousinstruments are described with reference to the embodiment of the accessdevice 300 illustrated in FIGS. 3A-3C, although those skilled in the artwill understand that the discussion is also applicable to otherembodiments described herein.

FIG. 3D is a cross-sectional view of the access device 300 with aninstrument I inserted off-axis into the access channel 302. In theillustrated embodiment, the axis of the instrument I is left of theaccess channel 302. The compression element 360 floats to the left,which shifts the orifice 352 of the instrument seal to the left whilemaintaining a seal with the instrument I. The orifice 352 of theinstrument seal tracks lateral movements of instruments, therebyreducing the likelihood of “cat-eye” leaks in which a trailing edge ofthe orifice 352 loses contact with the instrument I. The amount ofside-to-side motion that the instrument seal 350 will accommodatedepends on factors including the distance between the first end of themembrane 382 and the sealing orifice 352, and the diameter of themembrane 382.

The illustrated embodiment of the access device 300 also exhibits lowerhysteresis compared with a typical septum seal when moving theinstrument I longitudinally in the instrument channel 302, that isinserting, withdrawing, or changing direction. Because a septum seal istypically flat or conical, advancing the instrument I followed bywithdrawing tends to oil-can or pop the septum from a concave to aconvex shape. The instrument drag perceived by the user on this changein direction is different from the uniform drag experienced during theinsertion phase. On continued withdrawal of the instrument I, the septumremains in the convex configuration and the user again experiences auniform drag. Changing direction again pops the septum back into theconcave configuration, again, with a sudden change in drag.Consequently, the user experiences hysteresis in the drag on cyclicalinsertion and removal of the instrument I.

In the illustrated device 300, the sealing orifice 352 of the instrumentseal is coupled to the seal housing 330. Therefore, changing directionfrom inserting to withdrawing the instrument I adds only the weight ofthe compression element 360 to the withdrawal force. Furthermore, thefirst ring 384 and the second ring 388 restrict axial or longitudinalmovement of the compression element 360, thereby further reducinghysteresis. In some embodiments, axial movement of the compressionelement 360 is further restricted, for example, by disposing thecompression element 360 in a conical support or other support structure.Consequently, the instrument seal 350 has comparatively predicableinstrument-movement characteristics in which the surgeon experiences thesame drag force and “feel” of the instrument I during insertion andremoval. This consistency assures the surgeon that the instrument seal350 is operating properly, reduces trocar cannula displacement, andreduces fatigue of the surgeon from manipulating instruments throughoutthe operation.

FIG. 3E is a cross section of the access device 300 with a largerdiameter instrument I inserted off-axis into the access channel 302. Aswith the embodiment illustrated in FIG. 3D, the compression element 360shifts laterally to accommodate the off axis instrument I, as well asincreasing the size of the opening 366, while maintaining the seal atthe orifice 352. As discussed above, in embodiments comprising acompression element 360 with a lower modulus, a user will experience amore constant instrument drag with both the larger diameter instrumentillustrated in FIG. 3E and the smaller diameter instrument illustratedin FIG. 3D.

FIG. 3F is a cross section of the access device 300 with an instrument Iapproaching the instrument seal 350. The illustrated instrument Icomprises a forked, pointed tip, which is considered a difficultgeometry with respect to potential damage. Such a geometry is found, forexample, in some clip appliers. The hourglass shape of the membrane 382creates a funnel or ramped entry to the orifice 352, thereby reducingthe likelihood of damage thereto. The analogous orifice in a typicalseptum seal is typically the most vulnerable portion thereof. Contactbetween the tip and the membrane 382 also causes the instrument seal 350to pendulate away from the tip, thereby further reducing potentialdamage.

FIG. 3G is a cross section of the access device 300 with an instrument Icomprising an undercut U in the instrument seal 350. Undercuts areanother difficult geometry with respect to withdrawing the instrumentfrom an instrument seal, and are found, for example, in endoscopicstaplers. Again, the hourglass shape of the membrane 382 creates afunnel entry or exit to the orifice 352 for withdrawn instruments I,thereby reducing damage thereto. The smooth transition between thedistal surface of the membrane 382 and the portion around the orifice352 also reduces potential catches or snags. Furthermore, thecompression element 360 tends to move laterally in response to featureson the instrument, taking a path of least resistance, thereby reducingdamage to the instrument seal 350.

Moreover, the reduced friction between the instrument I and the orifice,the strength of the membrane 382, and the isolation of the compressionelement 360 from the instrument I also contribute to the improveddurability of the illustrated instrument seal 350 compared with atypical septum seal. Accordingly, the embodiment 100 illustrated inFIGS. 1A-1F in which the membrane 182 wraps the opening 166 in thecompression element will also exhibit improved durability and reducedlikelihood of damage from withdrawing instruments with difficultgeometries, such as undercuts and protuberances.

FIG. 4 is a cross section of another embodiment of an access device 400similar to the embodiments described above. The access device 400comprises a cannula 410 and a seal assembly 420. The seal assembly 420comprises a seal housing 430 and a cap 440. An instrument seal 450 and azero seal 490 are disposed within the seal housing 430. The instrumentseal 450 comprises an orifice 452, a compression element 460, and aninstrument contact element 480. The compression element 460 comprises agel disc comprising an opening 466. The instrument contact element 480comprises a tubular membrane 482 extending through the opening 466 ofthe compression element. The membrane 482 comprises a first end and asecond end, both of which are disposed proximal of the compressionelement 460, thereby “wrapping” and securing the compression element 460therein.

FIGS. 5-9 illustrate other embodiments of compression elements that areuseful in the access devices described and illustrated herein, as wellas in other embodiments, as would be understood by those skilled in theart.

FIG. 5 is a top view of another embodiment of a gel disc compressionelement 560 in which the opening 566 is star shaped. The points of thestar accommodate one or more of the folds or pleats in the membrane ofthe instrument contact element, thereby improving sealing to smallerdiameter instruments and/or in the absence of an instrument. In someembodiments, the slits or cut out sections in the opening 566 permit theuse of a thicker membrane and/or a lower elongation material for thecompression element 560, either or both of which improves the overalldurability of the instrument seal 550.

Some embodiments of the opening 566 have a different shape at a proximalend and a distal end thereof. Differences in a fold pattern in themembrane between the proximal end and distal end, and/or within theopening 566 can reduce the leak rate of the instrument seal by reducingor removing the gas leak paths.

FIG. 6 is a perspective view of another embodiment of a compressionelement 660 comprising a gel torus or donut. The opening 666 is narrowerat a center thereof, and wider at both ends. The rounded or arcuateopening 666 at the proximal and distal ends also reduces a strike planeof the compression element 660, thereby reducing potential cuts orpenetrations of the membrane.

FIGS. 7A, 7B, and 7C are top, side, and cross-sectional views of anotherembodiment of a frustoconical gel compression element 760. Thecompression element 760 converges from a first end to a second end,terminating in an opening 766. In the illustrated embodiment, the firstend of the compression element is reinforced with a ring 762 of gelmaterial. The opening 766 is also comprises a ring 764 of gel material.The illustrated embodiment is useful as the compression element, forexample, in the embodiment illustrated in FIGS. 2, 3, and 4.

FIGS. 8A and 8B are perspective and top views of an embodiment of acompression element 860 comprising a gel torus 861 similar to theembodiment illustrated in FIG. 6 and a plurality of radially extendingtethers 874, which secure the compression element 860, for example, tothe seal housing, thereby providing more precise instrument tracking.Embodiments of the tethers 874 also restrict longitudinal or axialmovement of the torus 861, thereby further reducing hysteresis. Each ofthe tethers 874 in the illustrated embodiment comprises a pleatedportion 876 that accommodates lateral movement of the torus 861. In someembodiments, the torus 861 and tethers 874 comprise the same material.In some embodiments, the torus 861 and tethers 874 are monolithic. Inother embodiments, the torus 861 and tethers 874 comprise differentmaterials, for example, a gel torus 861 and tethers 874 comprising amore rigid material.

FIG. 9 is a top view of an embodiment of a compression element 960comprising a circular rim 978 and a plurality of elastic elements orbands 979 arranged as chords across the circular rim 978, each rotatedwith respect to a longitudinal axis of the compression element 960. Eachelastic element 979 overlaps at least one other elastic element 979. Insome embodiments, the elastic elements 979 are arranged symmetrically.The elastic elements 979 comprise any suitable elastomeric material, forexample, gel, rubber, elastomeric polymer, and the like. The pluralityof elastic elements 979 together defines an opening 966 in thecompression element through which an instrument contact element isdisposed as discussed above. In other embodiments, the rim 978 hasanother shape, for example, oval or polygonal.

Some embodiments of the access device comprise a plurality ofcompression elements disposed along a length of a single instrumentcontact element. In some embodiments, the shape, dimensions, and/orproperties of the compression elements are selected to improve one ormore properties, for example, sealing a wider range of instrumentdiameters, achieving a more constant drag force, and/or reducing leakagewith no instrument in the instrument channel.

In some embodiments, the entire instrument seal is movable within theseal housing, thereby providing additional float to the instrument seal.In some of these embodiments, the instrument seal exhibits improvedsealing with off axis and/or angled instruments.

Embodiments of the instrument seal do not comprise actuators, dilators,or expander used in some instrument seals to pre-dilate the seal, or anymovable shields or protectors that pre-dilate and/or protect theinstrument seal. The membrane does not define a closed cavity or bladderin which air or an injected fluid defines or constricts the orifice ofthe seal, as well as restricting movement of the seal, for example,side-to-side motion.

While certain embodiments have been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopethereof as defined by the following claims.

1. A surgical access device comprising: a seal housing; an elasticcompression element disposed in the seal housing; and a non-distensibleinstrument contact element extending through an opening in thecompression element and a distal end of the instrument contact elementdisposed below the opening is secured to a ring, the ring arranged tomove freely within the seal housing.
 2. The surgical access device ofclaim 1 wherein the instrument contact element comprises at least oneslit.
 3. The surgical access device of claim 1 wherein the elasticcompression element is a zero seal in the absence of an instrumentextending through the instrument contact element.
 4. The surgical accessdevice of claim 1 wherein in the absence of an instrument extendingthrough the instrument contact element, the instrument contact elementat the opening in the compression element comprises a plurality offolds.
 5. The surgical access device of claim 1 wherein in the presenceof an instrument extending through the instrument contact element andthe opening of the compression element, the instrument contact elementseals against the instrument and spaces the instrument from thecompression element.
 6. The surgical access device of claim 1 wherein aproximal end of the instrument contact element above the opening iscoupled to an inner wall of the compression element.
 7. The surgicalaccess device of claim 1 wherein an inner diameter of the ring is aboutthe same as a diameter of the instrument contact element.
 8. Thesurgical access device of claim 1 wherein an inner diameter of the ringis greater than a diameter of the opening of the compression element. 9.The surgical access device of claim 1 wherein the instrument contactelement comprises a polyolefin film.
 10. The surgical access device ofclaim 1 further comprising a cannula extending from the seal housing.11. The surgical access device of claim 1 further comprising a zeroseal.
 12. The surgical access device of claim 1 further comprising astop limiting proximal movement of the ring.
 13. The surgical accessdevice of claim 1 further comprising a tensioning element urging thering distally.
 14. A surgical access device comprising: a seal housing;an elastic compression element disposed in the seal housing; and anon-distensible instrument contact element extending through an openingin the compression element and a distal end of the instrument contactelement positioned below the opening is secured to a disc weight. 15.The surgical access device of claim 14 further comprising a stoplimiting proximal movement of the disc weight.
 16. The surgical accessdevice of claim 14 wherein the compression element comprises a pluralityof elastic elements defining an opening through which the instrumentcontact element extends, wherein at least some of the plurality ofelastic elements overlap at least one other elastic element.
 17. Thesurgical access device of claim 14 wherein the compression element isdisc-shaped.
 18. The surgical access device of claim 14 wherein thecompression element is tethered to the seal housing.
 19. The surgicalaccess device of claim 14 further comprising a tensioning element urgingthe disc weight distally.
 20. The surgical access device of claim 14wherein the disc weight is movable within the seal housing.